Liquid-fuel-feed system



Oct. 16, 1928.

J. P. REMINGTON LIQUID FUEL FEED SYSTEM Original Filed Oct. 17. 1921FICi I.

WITNESSES:

ATTORNEYS.

Patented Oct. 16, 1928.

UNITED STATES- J'OSEPH PERCY REMINGTON, OF PHILADELPHIA, PENNSYLVANIA,ASSIGNOR TO REM- PATENT OFFICE.

INGTON MANUFACTURING COMPANY, or PHILAD LPHIA,'rENNsYLvANm, a

CORPORATION OF PENNSYLVANIA.

LIQUID-FUEL-FEED SYSTEM.

' Application filed October 17, 1921, Serial mobile is standin to whichgravity systems are liable, throug leakage at the carbureter needlevalve; the failure'of vacuum systems to furnish sufficient fuel at thevery times when adequate supply is most imperative, when running at highspeed and in hill climbing; and difliculty with the fuel supply owing toslight leakage of air from the system, as in tank pressure systems.While I prefer to feed the fuel under pressure, I am able to accomplishthis without the necessity of maintaining pressure in the supply tank.

Other objects and attendant advantages of my invention will becomereadily apparent from the detailed description which follows:

In the drawings, Fig. I is av more or less diagrammatic illustration ofan automobile fuel feeding system conventionally embody- I ing myinvention.

Fig. II is a'longitudinal sectional view of a deivce for feeding thefuel from the supply tank to the carbureter and controlling the flow offuel.

Fig. III is a horizontalsection of the pump taken as indicated by theline I IIIII in Fig. II.

In the fuel feeding system illustrated in Fig. I, the fuel storage orsupply tank is conventionally represented at 1, and the carbureter at 2.Between the tank 1 and the carbureter 2, interposed in the pipe conduitcomprising the sections 3 and 4, is a device 5 for feeding fuel andcontrolling its flow. This device 5 is connected by a pipe (3 with meanscapable of producing alternate impulses of rarification andcompressionof the air in said pipe, here shown as an impelleror pulsator 7. Thisimpeller or pulsator 7 comprises a cylinder 8 and a reciprocatory piston9 which may be actuated by any appropriate means, preferably the camshaft of the motorv to which fuel is to be supplied. As describedhereinafter, the pul- Ne. 508,076. Renewed September 24; 1927.

I sator 7 and the device 5 cooperate as a pump in feeding the fuel underpressure, and the device 5 may also include means for regulating itspressure and flow. 1'

By reference to the larger illustrations,

'Figs. ,II and III of the drawings,'it will be seen that the device 5comprises two up- 'right,'cyl indrical chambers 10 and 1 1, the formerof which I will term a pump chamber, and the latter a pressure chamberfor reasons which will presently become manifest. These chambers 10, 11are formed by cavities or cups 12 and 13 in a common basemember 14 andremovable caps or domes 15 and 16 screwed into enlarged brim flanges 17and.18 of said cup cavities. The dome 15 has a screw threaded axialextension. or nipple 19 for attachment of the coupling 20 of the pipe 6to the impeller or pulsator 7 The cup 12 of the .chamber 10 is similarlyprovided with an axial extension or nipple 21 for the attachment of thepipe conduit section 3 from the fuel supply tank 1.- Central stand 'pipe22 in the chamber 10 (forming, in effect, an inward extension of thepipe line 3) serves as ameans of trapping a portion of the fuel drawninto said chamber during the suction strokes of the impeller or pulsator7, as hereinafter explained. The displacement of the impeller or pulsator 7 is, in practice, made such that suflicienbfuel is drawn fromthe tank 1 at each suction stroke to substantially fill the pipe line 3and the chamber 10. Near its top, the stand pipe 22 is pierced with aseries of apertures 23 for the passage of the fuel. The pipe 22 isalmost wholly surrounded by a filtering screen 25 consisting of acylinder of fine wire gauze, which at its bottom, is held concentricallyspaced about the pipe 22 by an attached ferrule 26, and at its top by acap piece 27 which closes the top of said pipe 25. e The cap piece 27,it will be perceived, extends to a point below the level of theapertures 23, so that the V stream of incoming fuel is directeddownwardly and prevented from splashing up ward into the pipe 6 leadingto the impeller or pulsator.7. Upon removal of the dome 15, thefiltering screen 25 may be readily withdrawn'for cleaning whennecessary.

The cups 12 and 13 of the base member 14 are joined by a Web 29, andcommunicate through a duct in said web. This duct the chamber 11 has adepending extension or nipple which serves for the attachment of thecoupling 36 of the pipe conduit section 4 leading to the carbureter 2.In order that the pump device 5 may be readily secured to the dash boardor other fixture of the automobile, the base member 14 is provided withintegral extensions or wings 37-37 which are appropriately slotted as at3838 for screws or any other convenient securing means.

The operation is as follows:

During the first suction stroke of the pump impeller or pulsator 7, fuelis drawn from the supply tank 1 through theconstantl open conduit 3 and'into the chamber 10. uring the succeeding pressure stroke, fuel thathas been drawn in by the suction is forced through the duct 30, past thevalve 33, into the chamber 11, whence it flows to the carbureter 2.. Ifthe carbureter 2 is entirely empty at starting, a few strokes may berequired to expel air from the system through the carbureter, and tofill or charge the system (particularly the carbureter) with fuel. Uponclosure of the ,needle valve controlling fuel admission to thecarbureter 2 (by the accumulation of fuel in the carbureter) thesucceeding pressure stroke or strokes of the pulsator 7 can still passfuel through the check-valve 33 into the chamber 11 and accumulate itthere; but this can go on only until the resulting pressure of the airentrapped and confined in the 'dome 16 substantially balances thepressure impulses fromthe pulsa or. Accordingly, the building upofpressure in the system is limited'by the fact that flow of fuel Via thepipe 22 is absolutely free and unrestricted, so that fuel (and even air)from aboye the stand-pipe apertures 23 can always .return through thesupply conduit 3 to the tank 1, relieving any excess pressure due to thepulsator 7. In practice, the pres sure maintained in the chamber 11depends on the displacement of the impeller or pulsator 7; and I preferto so proportion this that a substantially constant pressure in theneighborhood of two pounds is maintained aid chamber s soon as thecarbureter needle valve pens again, even slightly, fuel will flow I fromthe chamber 11 into the carbureter 2 under the accumulated air pressurein said chamber 11. The next pressure stroke of the pulsator 7 will thenforce fuel'from the pump chamber 10 into the pressure chamber 11, andthence (if the needle valve still remains open) into the carbureter 2;while during the succeeding suction stroke, fuel drawn from the tank 1will replace. what has been injected into the carbureter. Such actionwill continue and recur so long as and whenever the carbureter needlevalve is open.

From this'it will be seen that while fuel is surged to and fro (or atleast inward) in the supply conduit comprising the pipe line 3 and thepump chamber 10 at every double stroke (suction and pressure) of thepulsator'7, yet it is only as and when permitted by the carbureterregulation'that the pressure impulses unseat the check-valve 33 and feedfuel through the delivery connection including the passage 30 and thechamber 11: i. e., only when-the outflow from the carbureter under thedemand for fuel (as represented by opening of the carbureter needlevalve) reduces the back-pressure in the chamber 11 that is maintained bythe needle valve when closed. When the carbureter 2 is full, the pumpautomatically ceases to be operative, except for idle surging of fuel;when the carbureter is taking fuel, the pump becomes operative, and thesurging'ceases to be idle, only to the extent of the demand. Any excessof the charge drawn into the chamber 10 on one suction stroke over thecurrent requirements is always permitted to return through the supplyline 3 on the succeeding pressure stroke.

It will be seen, therefore, that by reason of the absence of the usualcheck-valve or the like fromthe supply line 3, it is practicable to usean impeller or pulsator of sufficient displacement'to feed a quantity offuel exceeding any possible requirements, without incurring anysubstantial variation in the pressure under which the fuel is fed.

This delivery of fuel even with the conduit open toward the supply,without any check against return of excess fuel, is made possible byenergetic inward surging of the fuel. under rapid alternations ofsuction and pressure, such as results from actuation ot' the pulsator 7from an automobile engine as described above. For when the pulsator 7reverses at the end of a suction stroke and begins to exert pressure onthe fuel through the elastic fluid cushion in the pipe 6, etc, theinertia of the body of liquid in the supply line 3 serves as acheck-valve to allow the pressure to force the liquid'out through thecheck-valve 33 in the delivery (if conditions in the chamber 11 permit),--by virtue of the energy of the inward surge offuel induced by theprecedingsuction stroke, as well as of the energy due to the succ edingpressure inpulse. And since these efle is increase in an ever-increasingproportion with the speed of the engine and the frequency With thestand-pipe 22 in the pump chamber 10, moreover, an adequate delivery offuel at even the slowest speeds (as in cranking by hand) is safelyassured by the trapping of fuel in the chamber 10. For while the chamberis substantially filled through the pipe 22 at each suction stroke, yeton the succeeding pressure stroke the fuel below the holes 23 cannotstart to return, but tends to pass out through the check-valve 33 thevery instant that pressure makes itself felt in the chamber.

It is further to be remarlfied that notwithstanding the periodicity ofthe fuel delivery by the pump, the feeding of fuel to the carbureter 2is not intermittent, but continuous, owing to the air pressure head orcushion at all times maintained above the fuel in the chamber 11, whichcauses the fuel to flow to the carbureter in a steady stream so long asthe needle valve remains open. And besides equalizing the flow of fuelto the carburetor 2, the elastic cushion afforded the liquid in thedelivery connection by this chamber 11 absorbs the momentary peaks ofthe delivery pressure impulses from the pump, and thus cooperates Withthe free return of liquid through the supply line 3 in maintaining asubstantially constant and limited delivery pressure,well below anyvalue that might overpower the .carbureterregulation, force open theneedle valve, and flood the carbureter 2 with a supply exceeding thereal demand for fuel.

As regards the elastic fluid cushion through which the pulsator 7 actson the liquid fuel, it is to be noted that with the supply tank 1 belowthe pump device 5, as shown, preponderance of vacuum such as would causefuel to rise excessively highin the pump chamber 10 cannot occur,because the displacement on the pressure stroke of the pulsator 7 cannotexceed that on the suction stroke. On the other hand, preponderance ofthe pressure stroke arising from leakage of external air into the systemat the pulsator 7, or the pipe lines or connections, is alwaysautomatically corrected by expulsion of such air from the chamber .10into the chamber 11 and its ultimate discharge into the air chamber ofthe carbureter 2, which is open to the atmosphere.

When a pressure of 2 lbs. is maintained on the surface of the fuel inthe chamber 11, as hereinbefore described, the conditions for the feedof fuel are exactly the same as when the standard pressure of 2 lbs. ismaintained on the surface of the fuel in the supply tank of a pressurefeed systeml'such as heretofore used. For such parity of! operatingconditlons, my system only-requires a pressure of 2 lbs. to be raised ina chamber of a few cubic inches capacity, which can be done in a fewturns of the engine; whereas the other type of system requires 2 lbs:pressure to be built up in a large fuel tank,-which may be nearly emptyat starting. My system is, therefore, much quicker and more efficient instarting than a tank pressure system: indeed, with the partsproportioned, as hereinbefore described, to maintain 2 lbs. pressure inthe chamber 11, an ordinary carburetor can b filled in from 5 to 10seconds.

Inasmuch as the pulsator 7 is actuated from the cam shaft of the engineat onehalf the speed of the crank shaft, the range of variation of theimpeller speed is from Bl I about strokes per minute during cranking byhand to about 1500 for full speed of the engine,-or in the ratio'of 1 to100. Assuming acar travelling 10 miles per gallon of fuel consumed, itsrequirement would be 6 gallons per hour for steady operation at a speedof miles per hour, and almost twice this during rapid acceleration,aswhen the throttle is suddenly opened at a speed of 5 miles per hour andheld open until maximum speed is reached,-since under this condition thecharge is taken into the engine at atmospheric pressure, and the load isa maximum. Assuming that the motor needs 10 gal. per hour at the 3000 R.P. Mfspeed, its requirement at 300 ,B. P. M., as in idling wouldapparently be just as much, or 1 gal. per hour. However, the motor isunloaded in idling, and only takes in about of its piston displacement(owing to the 20 in. vacuum then existing in the intake manifold) ateach intake stroke; hence it would actually use only gal. in idling.

Besides the extreme range of the variations of speed and of the fuelrequirements indicated above, there is the extreme abruptness of thevariation in fuel demand represented by instant opening of the throttleof an idling engine. In other words, the fuel supply needs to beincreased thirty-fold on the instant; yet the pressure under which it isfed must remain approximately the same. These extreme requirements I amenabled .to meet by virtue of the unchecked return of excess fuelpermitted by the absence of the usual valves or the like from the supplyline. This, as already mentioned, allows a pulsator 7 of suflicientdisplacement to feed the requisite quantity in excess of any possiblerequirements to be employed, yet obviates excessive fuel supply at anytime and prevents substantial variation of pressure under even the mostextreme variations in operating conditions,as between high speed, whenthe carbureter needle valve is open most of the time, and idling, whenthe mg fuel, as required by the demand, even with the conduitsubstantially open at the supply side of the check-valve means; andpermitting fuel in excess of the requirements that is drawn inward bythe suction to return through the conduit under the pressure.

2. A method of feeding liquid fuel under pressure, in amounts adapted tovarying demand, in a conduit unchecked as against return of excess fuel,but with check-valved delivery; which method comprises exertingsufficiently rapid alternations of suction and pressure-on the liquid insaid conduit to surge the same inward under the suction impulses withsutficient energy to enable delivery to be made under the pressureimpulses, by virtue of the energy of the lDCOl11- ing fuel, as requiredby the demand, even with the conduit substantially open at the supplyside of the check-valve means; permitting fuel in the excess of therequirements that is drawn inward by the suction to return through theconduit under the pressure, and'at each passage of fuel through thecheck-valve means also trapping fuel at the supdply side thereof againstreturn as aforesa1 i 3. A method of feeding liquid fuel under pressurethrough a check-valved feed conduit to a carburetor with regulatedadmission, in amounts adapted to varying demand; which method comprisesexerting sufliciently rapid alternations of suction and pressure on theliquid at the supply side of the checkvalve means, through an elasticfluid cushion, to surge the fuel inward in the conduit under the suctionimpulses with sufficient energy to enable delivery to be made, by virtueof the inertia of the incoming fuel, when permitted by the carbureterregulation, even with said conduit substantially open toward the supply;and elastically cushioning the liquid in the delivery connection to thecarbureter and thereby safe-guarding the latter against flooding by thepressure 1mpulses.

4:. The processes of conveying liquid fuel from a source of supply to apoint of use through a system comprising a chamber amounts of use, evenwith the inlet substantially open;

and permitting the remainder of the charges to return through the inlet.

5. A method of feeding liquid fuel under pressure to a motor vehicleengine, in adapted to varying demand, through a system comprising acheck-valved feed conduit with a confined body of elastic fluidmaintained in contact with the liquid fuel at the supply side of thecheck-valve means; which method comprises exerting alternations ofsuction and pressure on the elastic fluid, with a frequency proportionalto the speed of the engine, and thereby surging the fuel inward in saidconduit with corresponding frequency, so that the varying inertia offuel in the supply end of the conduit for varying frequencies. ofalternation enables fuel which is drawn inward by the I suction to bepassed through the check-valve means under the pressure, as required bythe varying demand, even with the conduit substant'ally open at thesupply side of the check-valve means; and permitting fuel in excess ofthe requirements that is drawn inward as aforesaid to return through theconduit under the pressure.

6. A system of the character described for feeding liquid fuel underpressure, selfadapting to varying demand; said system comprising asubstantially closed checkvalved feed conduit, with a confined body ofelastic fluid in contact with the liquid fuel therein at the supply sideof the check-valve means, and means for exerting alternate suction andpressure on the elastic fluid and thereby surging fuel in the conduit;said conduit remaining open at the supply s de of its check valve meansto permit surging back and forth therein during periods 2f low demand,and the inertia of the fuel in the supply end of the conduit enablingdelivery to be made throughsaid check-valve means under the pressureimpulses, even with the conduit open.

7. A system for feeding liquid fuel under pressure, substantially closedfrom fuel supply to fuel delivery, and self-adapting, as hereinafterdescribed, to variations 1n the demand for fuel; said system comprisinga a pump with means of producing alternate suction and compression; acheck-valved delivery from said pump; a fuel supply ill] conduit to saidpump permitting return, under the pressure stroke of the pump duringperiods of low fuel demand, of fuel in excess of the demand that hasbeen drawn into the pump by the suction; and means for trapping in thepump a portion of the fuel drawn in as aforesaid, to prevent its return;the inertia of fuel in the supply conduit enabling the pump to deliverunder pressure without closure of said conduit, and the return of fuelas aforesaid preventing excessive pressure when the demand falls belowthe potential pump capacity.

8. A fuel pump comprising a pumping chamber containing gas, means forcausmg alternate compression and rarefaction of said gas, an outletpassage from said chamber having therein a check-valve, means torestrict the outflow through said valve at times to less than themaximum capacity of the pump, and an inlet conduit connecting saidchamber to a source of supply, said conduit being open to permit theliquid en-' tering said chamber in excess of the permitted outflow tosurge back through the said c onduit under the influence of thecompression of the gas, the discharge checkvalve being constructed andarranged to 7 open under the compression stroke by reason of the inertiaof the inflowing liquid, without closure of the inlet conduit.

9. A system for feeding liquid fuel under pressure to a motor vehicleengine, selfadapting, as hereinafter described. to variations in thedemand for fuel, and comprising a pump with an elastic fluid pulsator,driven by the engine for producing alternate suction and compression, acheck-valved delivery from said pump, and a fuel supply conduit to saidpump permitting return, under the pressure stroke of the pump duringperiods of low demand, of fuel in excess of the demand that has beendrawn into the pump by the suction; the inertia of fuel in the supplyconduit enabling the pump to deliver under pressure without closure ofsaid conduit, and the return of fuel as aforesaid preventing excessivepressure when the demand falls below the potential pump capacity.

10. A fuel supply system of the character described comprising acarbureter and its fuel admission valve, a pumping chamber with deliveryconnection to said carbureter, an elastic fluid pulsator forproducing-alternations of suction and compression in said chamber, and afuel conduit from the source of supply to said pump chamber which 'isopen during normal functioning of the device to permit back flow ofliquid whenever the resistance to outflow through the delive 'yconnection into the carbureter exceeds the operating resistance to suchback flow. I

11. A pressure-feedmg fuel supply system it inward under the suctionimpulses with sufficient energy to enable delivery to be made under thepressure impulses, when permitted by the carbureter valve regulation,even with said conduit substantially open toward the supply.

12. A pressure-feeding liquid fuel supply system comprising, incombination with a carbureter and its fuel admission valve, a

conduit leading to the carbureter from the supply unchecked asagainstreturn of excess fuel; an elastic fluid pulsator for exertmgsufficiently rapid alternations of suction and pressure on the liquid tosurge it inward under the suction impulses with sufficient energy toenable delivery to be made under the pressure impulses, when permittedby the carbureter valveregulation, even with said ,conduit substantiallyopen toward the supply; and a check-valve in the delivery connecti n ofsaid conduit to the carbureter adapted to remain closed under theback-pressure maintained by the carbureter valve when closed, and topass the fluid to the carbureter under the pulsator impulses when thecarbureter valve is open.

13. A pressure-feeding liquid fuel supply system-comprising, incombination with ,a carbureter and its fuel admission valve, a conduitleading to the carbureter from the supply unchecked as against return ofexcess fuel; an elastic fluid pulsator for exerting sufiiciently rapidalternations of suction and pressure on the liquid to surge it inwardunder the suction impulses with sufficient energy to enable delivery tobe made under the pressure impulses, when permitted by the carburetervalve regulation, even with said conduit. substantially open toward thesupply; and a check-valve in the delivery connection of said conduit tothe carbureter, with means affording an elastic cushion for the liquidin said connection and thereby safeguarding the carbureter againstflooding by the pressure impulses.

14. A pressure-feeding fuel supply system comprising, in combinationwith, a carbureter and its fuel admission valve, a pump with amotor-driven elastic fluid pulsator for producing'alternate suction andcompression and a fuel supply connection unchecked as against return ofexcess fuel, and a delivery connection to the carbureter with a pressurechamber and a check-valve; so that on the pressure strokes fuel may flowfrom the pump toward the supply as well as toward the carbureter, andflooding of the latter by the pressure impulses may be prevented. V

15. A system of the character described for feeding liquid fuel underpressure in a substantially continuous flow, self adapting', ashereinafter described, to variations in the demand; said systemcomprising a substantially closed check-valved feed conduit with anelastic fluid cushion at the supply side of its check-valve means, apressure chamber beyond said check-valve means, and means beyond saidpressure chamber for controlling the delivery from said conduitaccording to demand, so that back-pressure may be imposed on the fuel;and means for producing sufliciently rapid alternations of suction andpressure impulses on the fuel at the supply side of 'said check-valvemeans through said cushion to surge the fuel inward in said conduit withsuch energy that the inertia of the fuel in the supply end of theconduit enables delivery to be made through said check-valve means, evenwith the conduit substantially open at the supply,

side of said check-Valve means, whenever flow from said chamber underthe demand has reduced the pressure therein below that due to thepressure impulses.

16. A fuel supply system for a motor ve- 1,es7,7es a hicle enginecomprising a carburetor with means for controlling the admission of fuelthereto according to the demand, so that back pressure may be imposed onthe fuel; a pump with an elastic fluid pulsator for producing alternatesuction and pressure impulses, in frequency proportional to the speed ofthe engine; a cheek-valved delivery connection from said pump to saidcarburetor, provided with a pressure chamber beyond its check-valvemeans; and a fuel supply conduit to said pump permitting returntherethrough, under the pressure stroke of .the pump during periods oflow fuel demand, of fuel in excess of the demand that has been drawnintothe pump by the suction; the inertia of the fuel in the conduitenabling delivery to be made through said check-valve means under thepressure impulses, even with the supply conduit open, whenever flow fromsaid chamber under the demand has reduced the pressure in said chamberbelow that due to said pressure impulses.

In testimony whereof, I have hereunto signed my name at Philadelphia,Pennsylvania, this 29th day of September, 1921.

JOSEPH PERCY REMINGTON.

